Multiple myeloma (MM), a cancer that affects African-Americans disproportionately, is characterized by progressive and unremitting bone destruction. MM continues to be associated with high morbidity and mortality rates with no significant improvement in prognosis post-diagnosis in the last thirty years. The long-term goal of this proposal is for the Principal Investigator, Babatunde O. Oyajobi, PhD, to develop an independent career focused on developing novel therapeutic strategies to improve outcome in MM. In this Mentored Career Development Award application, the candidate outlines a plan that will enable him achieve this objective. Dr Oyajobi will use the KO1 to acquire additional skills in molecular biology and transgenic research and the co-sponsors, Drs Mundy and Hasty will provide an excellent training experience for the candidate in the 'state of the art'institutional facilities at UTHSC at San Antonio, TX. During year 1, the candidate will benefit from the co-mentorship of Dr Mundy, a renowned expert on effects of tumors on the skeleton, and of Dr Hasty, an expert mouse geneticist. During this period Dr Mundy will advise on biological experiments in mouse models of myeloma and Dr Hasty will provide training in specialized techniques in mouse genetics. By year 2, the candidate will be a fully independent investigator. Our hypothesis is that NF- kB activation is important for growth and survival of myeloma cells and tumor progression in vivo. The impetus for the proposal is the finding that expression in myeloma cells, of a dominant-negative (deltaF) mutant of the E3 Ubiquitin ligase betaTrCP/FWD1 that regulates NF-kB signaling, significantly reduced tumor growth in mice in vivo. The proposed studies now seek to elucidate the mechanisms mediating the effect of the transcription factor in myeloma. The Specific Aims of the proposal are: (i) To determine the contribution of the non-canonical NF-kB signaling pathway to myeloma growth/survival in vitro and in vivo (ii) To determine whether inhibition of NF-kB signaling in myeloma cells in established tumors results in tumor regression or reduced rate of tumor growth as well as prolongs survival in mice. The aims of this proposal will be addressed using a variety of approaches including transfection experiments, targeted transgenesis and in vivo (mouse) studies and other methods consistent with the proposed research career plan of the candidate. The research outlined will provide the basis for generation of novel therapeutic approaches to treat MM.